I think it depends highly on the individuals involved. Juvenile brain development differs greatly from individual to individual. I would argue that I was intellectually highly developed by 15, but not emotionally or socially, and some of my peers at the time didn’t have a realistic grasp of the world outside of school. Even if teens possess formidable reasoning power, their judgment is often poor at best.
They should be tried and punished severely for violent felonies, maybe 3/4 to 5/8 of adult sentencing severity (I just came up with that, its not scientifically based or anything), and life in prison or the death penalty should be off the table, except for the absolute worst offenders, especially those with gang ties and histories of violence. They are a real threat to society unless they are stopped, despite their age.
I think the prison system needs a restructuring though. Right now our system is wishy washy, it doesn’t punish enough, and it doesn’t do enough to get minor to moderate offenders out of a life of crime. We need two classes of jails, those that focus on building up individuals to rejoin society, and those that are focused on retribution and punishment. The inmates should go to the jails according to the crimes they commit. I think that for increasing severity, criminals should spend increasing amounts of time in the punitive facilties, and that all inmates spend a prescribed amount of time in the correctional societal rehab facility before they are released. This should be far more involved than a halfway house or any of the systems currently deployed. They need to be taught a skill so that they are able to provide for themselves when they are released, and they need to be educated to attempt to dislodge any potential ignorance that may have helped spawn their illegal behavior in the first place.
There are some criminals that will prove themselves to be either impossible to rehabilitate or extremely and defiantly resistant to rehabilitation, and they will become repeat offenders. We need a SANE law for crimes, dependent on their severity, that mandates gradual increases in sentencing for each repeat offense. I don’t advocate 3 strikes setups, except for severe felonies, as stealing gum 3 times doesn’t deserve life in jail no matter how you slice it. Once we give up on their future and put them away for good with no chance to get out, we should give inmates only minimal medical care to ease discomfort and attempt to forestall disease, but no lifesaving emergency procedures should be afforded to them, as they are a burden on the rest of society.
We also need better laws to protect minor offenders from job discrimination, but that’s a topic for another post.